1. Technical Field
The present disclosure generally relates to illumination devices, and particularly to an illumination device having substantially overlapping illumination areas of multiple lighting sources.
2. Description of Related Art
Joseph Bielecki et al. in IEEE, 23rd IEEE SEMI-THERM Symposium, “Thermal Considerations for LED Components in an Automotive Lamp.” characterize light emitting diodes as a kind of semiconductor device changing current into light of specific wavelength. Light emitting diodes (LEDs) have many advantages, such as high luminosity, low operational voltage, low power consumption, compatibility with integrated circuits, easy driving, long term reliability, and environmental friendliness; thus, LEDs have been widely promoted as a lighting source.
Many illumination devices in popular use utilize multiple lighting source modules with respectively different illumination areas. As a result, dark areas occur between the areas and illumination is non-uniform. Moreover, if one or more lighting source modules malfunctions, the corresponding illumination areas will be dark.
What is needed, therefore, is an illumination device which can ameliorate the described limitations.